Present methods for tumor treatment, especially cancer treatment, remain sub-optimal and often are accompanied by severe complications. In fact, virtually all of the known therapies have serious adverse side effects, most often caused by the lack of specificity and thoroughness in the destruction or removal of tumor or cancer cells.
For example, surgery, a common procedure for removing cancerous cells from a patient, often results in incomplete removal and disfigures the patient or interferes with normal bodily functions. Similarly, chemotherapy and radiation treatment often indiscriminately destroys normal cells, causing unwanted side-effects, while leaving many cancer cells unaffected. Chemotherapeutic agents, especially antimetabolites, while effective to varying degrees against cancer cells that are continuously undergoing or preparing for mitosis, are not effective against cancer cells that are in the resting (G0) stage.
Cancer treatment is most effective when cancer cells can be eliminated as completely as possible from the patient's body. To achieve this goal, continuous or consecutive dosages are administered to the patient. Because most available chemotherapeutic agents are also toxic to normal cells, the dose of cytotoxic drug is adjusted to the limits of tolerance to achieve the maximum destruction of malignant cells, and the interval between doses must be such that the rate of tumor re-growth does not exceed tumor killing. Accordingly, in order to achieve increased efficiency with reduced side effects, the chemotherapeutic agents should have high target-cell specificity and high target-cell toxicity or potency.
Prostate cancer is the most common form of cancer among males, with an estimated incidence of 30% in men over the age of 50. Overwhelming clinical evidence shows that human prostate cancer has the propensity to metastasize to bone, and the disease appears to progress inevitably from androgen-dependent to androgen-refractory status, leading to increased patient mortality. This prevalent disease is currently the second leading cause of cancer death among men. Prostate cancer metastasis is estimated to claim the lives of over 30,000 Americans each year. In spite of considerable research into therapies for cancer, currently available treatment methods are ineffective in a significant percentage of cases.
Accordingly, there is a need for improved cancer treatment and more methods that are not dependent upon the cell cycle of the cancer cell. Particularly, there is a need for improved treatment methods for prostate cancer. The present invention fulfills these needs and further provides other related advantages.